Structural archaeologist Geoff Carter's radical view of building in the ancient world, especially the archaeology of the lost timber built environment of Southern England. It is new research into of prehistory of architecture, available in a series of articles that are designed to be read in order, and to be accessible to the non-specialist - and there is even some humour

14 November, 2011

When I need to think about what to write next, I go and see my friend Daisy, and we go for a walk in the woods. She is a very good listener, but gets impatient with my interest in the trees, as hers mainly involves games with a stick. Thinking about trees is the basis of much of my research about archaeological structures, and for Daisy, sticks are the fundamental part our shared culture. Throwing sticks, in some form or other, is an important and fundamental human skill; as a retriever, Daisy enjoys the chase and hunt for the stick. Possession of the stick is the object of the game.

Each tree we pass can be viewed as a source of material for a whole variety of cultural artefacts, but you have to concentrate on Daisy, or you will miss her hiding the stick for you to find. Our wooden heritage is usually almost invisible to the archaeologist and lost to posterity, leaving us to conceive of the past in terms of tools, rather than product or materials. When the stick becomes lost or stuck in a tree, Daisy will locate a suitable fallen branch and attempt to break off a suitable piece so we can continue the game; Daisy is a tool-making dog.

Mission statement

Above and beyond walking the dog--well, certainly, above-- I am surrounded by trees. Thus it occurred to me to document the different species of trees I found on our walk: Each has a something of interest about it, and it follows on nicely from Vitruvius’s thoughts about trees discussed in a previous post.

Lacking a pen and paper, I decided to document each species using something that describes itself as a camera, built into my phone. Unfortunately, it has the memory capacity of a mayfly, which, it rapidly informed me, was full, ensuring more messing about with a device optimised to be operated by the hands of Chinese schoolgirl. Given weak and fading light, with a stiff breeze fluttering the leaves, this was never going to make it as a National Geographic photo feature.

Also, I have not brought a field guide with me, so I am winging it on the species identification. Try to think of this as a virtual field trip in the theoretical archaeology and history of trees.

Woods: Executive summary

Woods are big fields of trees; there is a main crop, and usually also weeds of cultivation. The crop needs attention at regular intervals, even if these are measured in years or even decades. The plants are thinned, the weaker and diseased are harvested, and the uninvited guests cleared. The cycle usually ends with the entire remaining main crop's being harvested.

Most modern woods are laid out and stocked for mechanisation. However, in the past, when woodland was tended manually, more complex mixes of species and ages were usual.

It is possible to read a wood. Its current phase of production is by and large self-evident, but occasionally there are clues to older management regimes reflected in aspects of the ecosystem. Woods, like other aspects of the landscape, are created through a long interaction with man, and thus have a relationship with our wider narrative history.This wood is in Cumbria, in the north of England. It's early November and some trees have already dropped the majority of their leaves.

The woodland is fairly mature commercial softwood, mostly Norway spruce, larch and Scots pine planted in blocks.At first glance, it's not that interesting; only the Scots pine is a native tree. But in maturing woodland there is space and light underneath the canopy, and an understory of self-seeded and deliberately planted young trees has developed. In odd corners, there are survivors and decedents of earlier woodland regimes, and on one edge, a block of mature fir was harvested, revealing the understory of smaller trees and shrubs. [above seen in Sept]

This wood is mostly situated on a well-drained small hill, bordered by a road, a railway, and the derelict grounds of a county house.The latter is important if we are looking for a competitive species count.

To keep this narrative in some way relevant to archaeology, I will break the trees down into natives and foreigners.

The Natives

In terms of simple numbers, the most common are probably the native trees, those species that colonised the area following the ice age, and are still the most dominant among the informal population of the wood.

Alder (alnus glutinosa)

We start with a tree that I choose to identify as an alder: It is a shrubby specimen by the railway. It's usually found next to rivers or areas of poor drainage. Alder is mentioned by Vitruvius, although for use only as piles for building in waterlogged conditions. Interestingly, it was used in the making of the Roman wooden water pipes found preserved at Vindolanda.[1]

The wood is not valued for carpentry, although it was the best material for clogs, but alder has an important cultural connection: It was the preferred tree for the production of charcoal, particularly for gunpowder, which gives it a certain historical significance. In addition to its chemical uses, charcoal was an important industrial fuel until well into the Industrial Revolution, more or less essential for iron or glass working.

Charcoal-making was done in ‘clamps’, 15’ diameter mounds of earth and timber that contained and sealed in the timber that was burning under reducing conditions, a process that took about 10 days.

While archaeologists frequently identify burnt mounds, areas of burnt debris of various ages, often associated with river valleys, I am not sure if any have been associated with charcoal burning. It takes about seven tonnes of wood to make one ton of charcoal. Processes like the prehistoric smelting of copper required a disproportionate amount of timber, such that it was often easier to transport the ore to the wood.

Ash (Fraxinus excelsior)

This tree is one of the first to shed its leaves and last to deploy them in the spring, but is easily spotted because of its silver bark and black buds. It was one of the most important of the native timbers. Its timber is tough and elastic, easily worked, and splits exceptionally well. Think of it as a good material for absorbing shock. It was the ideal for handles and shafts, from hammers to lances. It was traditionally used in wheel making, and in coach building, where it would be used for the shafts of wagons. Ash was an important material when aircraft were made of wood. It tends to fall prey to woodworm, and is not often used in buildings, although Vitruvius recommends it for pegging joints. It is also good firewood that dries well, yet another important quality.

Beech (Fagus sylvatica)

Although with its silver bark and turning leaves beech draw attention to its presence, it is probably the commonest of the native trees, with mature specimens marking the boundary of the wood and saplings well- represented in the shrub layer. There is even a block of saplings under-planted at 4’ centres in an area of mature Norway Spruce in the middle of the wood.

Beech is another tough and useful hardwood. It's not durable enough to be used outside, but it was the staple of the furniture maker, particularly for chairs. It was also traditionally used for flooring, agricultural implements, carpenters' benches and some tool handles. Another historical use for beech was for the manufacture of gun-stocks (although walnut was usually the premium material for this type of work).

Beech, although very susceptible to a variety of diseases, is generally very long-lived and reaches impressive heights, is often found on boundaries, and can make a very decorative hedge.

Planting trees is an important way of marking or establishing a boundary: It is very difficult to obliterate boundaries formed by mature trees, and they can become significant features in the landscape.

Birch (Betula pendula)

This tree is traditionally one of first colonisers, a tough diminutive pioneer. Birch woods are usually self-seeded, but in the long term, they are usually out-competed for the light by taller species.

Although best known for making of brooms, of the ‘witches broom' model, it also was one of several woods used for clogs, and like ash, was used for making arrows in the medieval period.[2]

It is a utility wood in joinery and cabinetmaking, a term that covers the manufacture of things like furniture and containers, where its wood may be used for its decorative effect or to back wood of higher value. There is a whole range of techniques involving mixing woods of contrasting colours and textures, often using thin veneers, cut as the technology allowed.

Mechanised woodworking and processing has allowed the creation of wood composites from thin layers and boards made from compressed waste wood that can be engineered to specific standards of strength and stability. One of the fastest and most effective planes of the Second World War, the de Havilland Mosquito, was mostly made from birch plywood.

Blackthorn (Prunus spinosa)

This is another fairly inconspicuous hedgerow tree, known for its dark berries called sloes, which are so bitter they are seldom used for anything other than flavouring gin. It can be a seriously spiny tree, and its wood is very hard, and was traditionally used to make clubs and sticks, like the Irish shillelagh.

Box (Buxus sempervirens)

[No photo--way out of focus]

This species does not belong this far north, and occurs as a piece of outgrown topiary courtesy of the derelict estate, which was probably the main source of all the more exotic trees on the list.

However, box is an historically important species of tree. Its slow growth produces a hard fine grain that was much sought after. Engravers used its end grain for printing, and it was much valued for turning and cabinet making; it was a premium material for wooden combs.

Bird Cherry (Prunus padus)

Members of this family are fairly inconspicuous trees, but important for their fruit. This reminds us of the importance of trees and sources of fruit and nuts both in the ‘wild’ and as part of the agricultural mindset. Generations of growers have chosen to plant the seeds of trees that had performed well, and as with other crops, slowly developed the qualities of the species.

In terms of timber, cherry is traditionally used in cabinetmaking, where it was valued it for its grain and colour. It thus joins the list of trees that were valued for specific applications, but generally not required in sufficient quantity to be grown on a commercial scale. Wood from other fruit trees, including apple, is often highly valued for making a variety of specialist artifacts. Cherry makes good firewood that burns with a fragrant smell.

Elder (Sambucus nigra)

This is a familiar plant, perhaps more of a shrub, that reminds us that trees were used for medicines. It is also one of those trees we could even tentatively discuss in terms of its magic and symbolism (or perhaps not).

The fruits and flowers of elder make excellent beverages, and it is one of many woodland plants that would be harvested in season to supplement the basic agricultural fare.

Elm (Ulmus sp.)

There is some debate about just how native the elm tree is, and there are several varieties and regional variations. It is perhaps best known for Dutch elm disease, which has greatly depleted numbers in the English countryside.

Elm is tough hardwearing timber, used for things like lining ships and wagon floors, as well as chair seats and coffins – it lasts well underground. Its twisted grain makes it difficult to split, so its utility has developed along with sawing technology, but this also makes it perfect for piles or stakes. In addition, since it is very long-lived when immersed in water, it is an excellent material for building bridges, jetties, and docks.

Hawthorn (Crataegas monogyna)

This thorny twisted small tree is the basis of many hedges and can be readily trained into an impenetrable barrier. It is a simple process to establish, train and maintain a hedge, and this is an important method of enclosing and protecting space. Hedges are easier to establish without a bank and ditch and thus can be difficult to detect archaeologically.

Hawthorn is not a tree beloved of the carpenter, but it is very hard and nicely figured wood and, like blackthorn, might serve as a source of sticks and clubs.

Holly (Ilex aquiflorum)

We are all familiar with Holly, and this touches on the role of trees as a symbol or embodiment of something or someone. Most trees have a folklore, associations, both Christian and Pagan, that integrate them into the wider narrative and religious culture.

Holly is hard, dense, close-grained timber, so in historical times, like box, it was used in engraving and printing. It is good wood for turnery, another important wood industry with a long historical tradition, which may have developed in the late Iron Age.

Holly was the wood chosen to make the singel [swipple], the business end of a flail, the essential tool for threshing wheat. Of all the native timbers, it burns with the hottest flame, so it might be regarded as premium firewood.

Rowan, mountain ash (Sorbus aucuparia)

This is one of our hardiest tress, growing at high elevations, in most soils, and in all aspects. However, it is not a very big tree and is unlikely to be grown commercially, except to nurse young conifers. In this context, it might also serve as fire belt.It is often planted for ornamental purposes. The timber of the mountain ash is tough and was used for cart-making and agricultural implements.

Oak (Quercus sp.)

As a founder member and dominant species of much our natural woodland community, oak was a focal part of a complex and diverse ecological community that is now only partially preserved. The original wild wood, and the later woods and forests that developed through the agency of man's interventions, were the sources of much of what was not produced from fields and gardens. While other ecological zones were of importance, woodland was the most productive. Acorns were foraged by pigs, both domestic and wild, which leads us to the use of forests for leisure.

In an historical context, this was usually hunting and blood sports, principally the preserve of the landed classes, who usually maintained exclusive rights to or control or ownership of the resources embodied by large tracts of wooded land.

I found three types of oak on my walk: Sessile or Durmast Oak (Q. petraea)[below], the dominant species this far north; the familiar English Oak (Q. robur)[right]; and an exotic Red Oak (Q. rubra) that comes originally from North America.

The sessile oak [left] may be generally distinguished by having marked stalks on its leaves, but not on its acorns, the pattern being reversed for English oak. However, acorns are not evident on these young trees squatting under the canopy of commercial conifers.

One tree near the edge of the wood was effectively a coppiced tree, with multiple stems. Although this may indicate an earlier phase of use, it can also be the result of accidental damage. [Below]Coppicing to produce multiple stems on a single root system, or stool, is a simple way of producing large amounts of small and medium diameter wood, where bulk crops are required. From basketry to building, coppiced production is an essential part of a traditional woodland regime, often mixed with ‘standard’ trees and occupying the shrub layer, or ‘underwood’.

Generally, oak timber is exceptionally strong, tough, and durable, ideal for construction work, being used for buildings, ships, bridges, and things like mill wheels. Traditionally it was extensively used for furniture, cabinet making and carriage building, and it was the preferred material for barrel staves, treenails and gates. The timber of sessile oak is softer and more easily worked than that of the English Oak, so the latter would usually be chosen for structural work.The suitability of oak timber for a huge range of applications, coupled with its wide availability, make it an important factor in the economic and social history of these islands.

Scots Pine (Pinus sylvestris)

This native conifer replaced oaks as the dominant forest species further north, in Scotland. It is important commercial timber, although as a native, it is disadvantaged by attentions of local insects and fungi, which is why commercial woodland so often features foreign trees, in this case spruce and larch.

Pine is one of those ubiquitous soft woods, or ‘deals’, which are utility woods of the building industry. Just as discussed by Vitruvius, their value depends on how they are grown. Modern systems that grow single-species crops very close together are designed to minimise branching and maximise height through light competition. Producing a consistent product with the minimum of wastage, which requires little attention, is ideal for mechanised production.

Softwood is light, easily worked and a comparatively strong material. Its modern importance in house building and furniture making reflects its relative abundance, since, traditionally, softwood was, in most applications, a second-class material.

The previous discussion of Vitruvius also reminded of the importance of resins and oils extracted from trees. Like charcoal, until the widespread exploitation of mineral deposits, plants and trees were the source of many ‘chemical’ preparations.

Pine burns well and easily, not a good property in a building material, but of merit in firewood, although its tendency to spit and spark is something of a drawback.

Yew (Taxus baccata)

But for its reputation for making bows, it might be easy to overlook this small native conifer. It is also notable for being very poisonous to cattle, which has been used to account for its frequent presence in church yards, although alternative accounts revolve around its symbolism and veneration. It is very slow-growing small tree seldom reaching more than 30-40’, but often achieving great age.

Yew wood provides by far the best material for making bows, and as such it has made a significant contribution to our history. However, the yew used for medieval bows may have been imported, reminding us again that some wood can be a premium product subject to trade over long distances. Bows were important in the ancient world, and weapon-making is a perfect example of a craft where the optimum materials would be sought and used.

More generally, the wood is tough and durable, makes fine furniture, and is even exceptionally long lasting when used in the round for posts. The Vikings used it for the treenails that secured the planks of their clinker built boats.

Non-Native species

After 16 species, our tour of trees has all too soon run out of natives, and we now are making the numbers from the extensive population of naturalised immigrants, many with an archaeological heritage.

Chestnut(Castanea sativa)The wood we are visiting is perhaps unusual in having a healthy population of young chestnut saplings, not a particularly common woodland species this far north. It is thought that the Sweet Chestnut was introduced by the Romans, who produced flour from the nuts, which we traditionally eat around Christmas time. The timber was used in furniture making and house interiors. It is quite durable and has traditionally been used for posts and poles, such as hop poles (hops = beer). It splits readily, and is perhaps most familiar as ‘chestnut paling,’ a fencing formed by vertical split timbers joined by wire.

Lime (Tilia x vulgaris)

Another introduced species, lime is a good example of a tree widely planted for its ornamental value, but seldom as a commercial timber. It is also a good example of a poor firewood. Lime wood is easily worked, even-grained, and resists splitting; it was typically used for all types of carving. This extends to items like toys, artificial limbs, and founder models, the patterns used to form moulds into which molten metal would be poured.

Lime is an untainted wood, suitable to make items that came into contact with food and was used to make the frames for beehives.

Acers are another widespread and familiar group of trees, particularly the sycamore. Like the lime, these trees are often planted for decorative effect, but they also are vigorous self-seeders and quite invasive.

Their timber has a variety of important specialised uses. Sycamore wood won’t stain or taint food, so it was used for making things like pails, milk churns, and kitchen surfaces; and for domestic utensils like spoons, bread boards, and even the rollers of a traditional mangle.

The wood is often nicely figured and is a favourite among musical instrument makers, who use it for the bodies of violins and other stringed instruments.

Larch (Larix decidua)

This conifer that loses its needles in winter has long been a staple of commercial softwood production. Similar to pine in its uses, but one of the most durable of the softwoods, it is preferred for fencing and other outdoor applications, referred to as ‘estate work’. We have previously discussed the Roman ‘discovery’ of the larch, a tree discussed at some length by Vitruvius, who made the point that it did not burn well.

So this is good point to note that utility of timber for firewood varies greatly with species. Firewood has to be cut, split, and dried, in suitable quantities and sizes to suit the nature of the fire. Thus, ease of processing, speed of drying, and availability are all concerns in the choice of firewood, as well as the burning quality of the wood itself. Drying is most important and takes many months. If you are a poor man gathering winter fuel on the Feast of Steven, you have missed the boat and are in trouble.

Norway Spruce (Picea abies)

Norway spuce is another commonly grown softwood, best known to most people as the ‘Christmas tree’: a young tree killed and brought into the house to share the festival. It is dressed in gaudy decoration, and then largely ignored, until it drops its needles in a spirited attempt to infiltrate the carpet and destroy the vacuum cleaner.

Spruce is an important softwood, which in addition to its role in construction, is used in the manufacturer of things like packing cases, musical instruments, and toys. It is commercially important as pulp wood for a making paper and card. It can be cleft into thin sections that do not warp, ideal for things like Venetian blinds and more importantly, the sounding boards for pianos and the bellies of stringed instruments like violins and cellos. Thin strips of spruce can be woven into baskets or even mats.

Decorous Exotics

As a result of centuries of interest in planting trees, not only as commercial crop, but also to improve the landscape, some rather more ornamental trees supplement my species count.

They are usually too recent introductions to be of great historical or archaeological interest. I did not photograph them, apart from the Red Oak [above], and the large conifer protruding above the canopy of a some pretty tall beeches; I think this is a Douglas Fir [Pseudotsuga menziesii][right].But it actually is a Giant Sequoia (Sequoiadendron giganteum).

However, I did see a laburnum (Laburnum anagyroides), which was traditionally used to make bagpipes until the introduction of more exotic imported woods.

To complete the count, I encountered a copper beech, rhododendrons, and a flowering cherry. I think a saw a native whitebeam [Sorbus aria] in a hedge. It was getting too dark to photograph it.

Hazel: one of our trees is missing

That is a species count of twenty-nine(ish), not bad for an hour's dog-walking in a commercial softwood plantation. Further and more thorough exploration of more distant comers might have turned up more species. However, one tree I failed to note is very surprising: That was hazel (Corylus avellana), probably the most important of the smaller trees grown below the canopy, usually as a coppice, in traditional woodland. Its long straight stems were used whenever rods or flexibility were required. Hazel was the natural companion tree for the oaks that formed the rigid components of a building, and it was the basis of wattle and daub walls, and provided the spars, pegs and runner that secured a thatched roof. Woven into panels, or hurdles, it was invaluable for fencing and handling stock.

Walking sticks are perhaps the oldest technology of all, and the familiar shape relies on bending woods like hazel, willow, and ash into shape using heat.Usually young flexible stems are steamed or immersed in hot sand, then bent and held to the required shape. This is how things like wooden hoops and the curving backs of traditional chairs were made.

With hazel we touch on a vast range of uses for bent young stems, like baskets, fish traps, and crates. This also includes coracles. These skin-covered boats had frames woven like a basket. However, more rigid components might be streamed into shape, or some suitably curved branch could be split down the middle.

Splitting suitable branches to produce two matching components was also an important technique in oak shipbuilding, to such an extent that, contrary to normal practice, some oaks were grown spaced far apart to encourage side-branching. Splitting suitably curving trunks was also the basis of the ‘cruck’, a form of roof truss, which can still be seen in some surviving ancient buildings.

One final observation was honeysuckle, a vigorous climber that can be seen working its way clockwise up the stems of younger trees.[right] It is the most obvious material of which to make ropes and bindings, and was found to have been used to drag the oak trunk used in the building of the Seahenge monument during the Bronze Age.[3]

Conclusions

The trees that Daisy and I passed on our walk touched on numerous aspects of transport, agriculture, building, warfare, leisure, and creative culture, and hinted at how woodland reflects and responds to changes of technology and economic circumstances. They represent a significant and strategic resource that was fundamental to the majority of material culture, as well as an important source of food, fodder, and fuel. This in turnleads us inevitably to the issues of ownership and power that drove the narrative of history.

Archaeology has a problem in understanding these issues. We often find the craftsman’s tools, but not the products, and this can distort our view, a problem exacerbated by our present-day material culture, which has distanced us from our traditional relationships and understandings of wood, timber and trees.

We easily forget that the railways of the Industrial Revolution ran on wooden sleepers, that roofs of mines were supported by wooden pit props, and that Wedgwood china was transported in hazel crates on wooden barges, along canals with brick bridges and tunnels built using timber formwork.Largely unseen in the ancient countryside, and lost to archaeology, generations of woodmen, bodgers, charcoal burners, and wrights and makers of many diverse items, were busy splitting, bending, cutting, and carving wood to fabricate much of our material culture.

One very basic, but fundamental, point about their craftsmanship in wood was the choice of the appropriate materials for the task in hand. A traditional wheel would be made with an elm hub, oak spokes and ash felloes; and then so on throughout the cart, wagon or chariot. While there is someroom for compromise, if you use ash, or almost any timber other than elm for the hub, the technology simply won’t work.

The nature and properties of the available timbers will effect the underlying design and technology of most aspects of a material culture, and through this, its archaeology and history.You need a good stick for a proper game of stick, so Daisy and I both spend time seeking out the best sticks, suitable for carrying around in your mouth, and with just the right properties for throwing a long way, enhancing the quality of the experience for both of us.STOP PRESS

My own internal editor can’t live with the thought that some issue of fact might be wrong, and I’ve been back to take a closer look at the large conifer I had thought at a distance might be a Douglas Fir [Pseudotsuga menziesii].

I was quite wrong. It is in fact a Giant Sequoia [Sequoiadendron giganteum]. In Britain, the common name for this tree is a Wellingtonia, a name given it by John Lindley who officially named it Wellingtonia gigantea in 1853, after the Duke of Wellington, who had died the previous year. Unfortunately, he already had a tree named after him.

This is good point of return in the recent narrative about trees, which started in the previous post with the story of Julius Caesar’s discovery of the larch as told by Vitruvius, and ends with this giant of the American Pacific coast, named for a great war leader turned politician, nineteen centuries later, using, appropriately enough, the language of the Romans.

Geoff, what an amazing post and so comprehensive. Many of these trees are native to where I now live as well, and you've helped me to learn so much more about them. I'll have to return here periodically to refresh my memory. Hope all is well.